Process of working explosive-engines.



ma. SGERBBER. `PROGESS 0F WORKING EXPLOSIVE ENGINES.

lAPPLIGATION FILED NOV. 27, 1903.

Patented Sept. 15, 1908.-

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KARL EDMUND SCHREBER, OF GREIFSWALD, GERMANY.l

PROCESS OF WORKING EXPLOSIVE-ENGINES.

Specification of Letters Patent.

Patented Sept. 15, 1908.

Application led November 27, 1903. Serial No. 182,785.

To all whom it may concern:

Be it known that I, KARL EDMUND SCHRE- BER, a citizen of thev Empire of Germany, residing at Greifswald, German in the Province of Pomerania and King om of Prussia, have-invented certain'new and useful Improvements in Processes of Workin Ex losive-Engines, .of ,which the following 1s. a

the object thereof is to provide a method of specification.

My mvention .relates to a process or method of operating explosive engines, and

cooling the medium under com ressionl by the piston, in order to maintain t is medium below the ignition point of the explosive mixture, which method will Give a higher efliciency of work than other known methods of which I am aware.

The general obj ect sought by my invention has been, to a certain degree, attained by engineers, but so far as I am aware, the methods heretofore followed have involved the mixing of the cooling agent with the explosive mixture before or at the time the same is introduced into the cylinder or .to inject the cooling agent alone into the cylinder, in both cases no special reference being paid 'to the degree of heat of the medium under compression at the time of the introduction of said agent, or to the degree of increase of temperature of said medium under the continued compression of the same.

In contradistinction to these known methods, my method com rehends the gradual introduction of the coo 'ng agents directly into the cylinder, said introduction commencing only after the medium under compression has attained a predetermined temperature.

By the present invention the internal cooling is eHected with the employment of the least ossible quantity of cooling medium, so that t e compression can be carried past the limit hitherto attainable. For this object a liquid requiring a suitable amount of heat for evaporatlon is injected or s rayed into the interior of the working cylin er in such a way that the injection begins after the inflammable mixture, or rather the air not yet mixed with inflammable material, has been heated up to the evaporating temperature of the injected liquid corres -onding to the existing pressure. From t is point onwards the 1n ection must take place so gradually that'tlie heat'producedby the com resslng work done lduringa known part o the 1n- 'crease in pressure shall just suffice toevaporate the cooling liquid injected during the same time.V Care must also be taken to effect a sufficient distribution of the injected liquid through the whole interior of the cylinder. In large engines it may be necessary to divide u the inlet passage into several parts in or 'er to effect this object, and in this way the greatest possible amount of the mixture, or rather air, to be compressed may be cooled by the liquid.

The liquid employed for the internal cooling must possess a suitable heat of evaporation; water must also be taken primarily into consideration. But if li uidinliammablematerial or fuel is employedl in the explosion engine the heat of evaporation of this material may under certain circumstances be sufficient. I If that is not the case, the heat of evaporation may be raised up to the proper value by the admixture of water with the liquid fuel, sup osing such mixture to be possible. If suc mixture is not possible and at the same time the evaporating heat of the liquid fuel is insufficient to produce the cooling, then water must also be injected in ad-, dition tothe fuel. Whether or not the two liquids can be injected simultaneously, or one after another, and in the latter case in what order they may be injected, depends upon the nature of the fuel or inflammable liquid; but in any case the order of succession can always be so arranged that the heat existing in thegas Within the cylinder owing to v rate evaporating apparatus will be rendered unnecessary.

In order to better explain how this invention may be applied in practice it will be described with re erence to a spirit motor working u on this principle. This motor is illustrate in the accompanying drawings Vin which Figure 1 illustrates the whole arrangement of the motor, and Fig. 2 shows a part of the cylinder head in section.

In spirit motors, as alsoin all motors upon this principle and working with liquid inflammable material, pure atmospheric air is drawn in during the indrawing stroke, and on this account these motors canbe readily constructed as two-stroke cycle motors. In the 'form of spirit motor shown the back of the piston a, will serve for the drawing in of air, the crank casing b being made' air tight. During the compression stroke-of the' piston air will be drawn into the crank casing through a self acting valve c, and will be slight y compressed in this casin during the expansion stroke. Supposing t ton is approaching the end of an expansion stroke, 1t will uncover and open the exhaust slots d formed in the cylinder casing, and the ases of combustionwill escape into the exaust ways. As soon as the ressure in the cylinder w has fallen suflicient y the self-acting air inlet valve e arranged in the cylinder head opens, and the air under slight pressure streams from the crank casing through the pi e into the cylinder lw from which it expe s efore it the remainder-of the gases of combustion. The guiding part of the main piston must ofcourse be of such a length that it always keeps the exhaust slots d closed to the side of the crank casing. When the piston again advances in the direction of compression it closes the exhaust slots and then the compression of the air contained in the cylinder commences. As soon as the temperature of this air is sufficiently raised by the work of compression the injection of the spirit is'begun, more or less of the amount of s lrit required for the cooling being supplie by water according'to the excess ofairh.,

with which the explosive mixture is to be made. The injection can be so adjusted by suitable regulating devices that the temperature in the cylin er obeys asuitable predetermined law. For example, if the temperature is to remain constant during the injec-l tion, the injected mixture must obey the law:

fu. n. A=const.

Where fv is the volume existing at the moment in front of the piston, n is the number of molecules contained in this volume, and A is a constant de ending u on the heat of eva oration of tlie injecte li uid and the pre etermiped temperature. vantageous to allow the temperature. to rise slowly so that it always remains somewhat higher than the boiling temperature of the injected liquid correspondin to the existing pressure. lf the speed of t e injectionis so measured that in normal workin the necessary amount of the inliammable 'quid is already injected somewhat before 'the endof the stroke, it is possible for the working of the motor to be regulated by adjustment of the feed in exactly the same wa as in steam engines. The com ression fo owing after the termination of tIfie injection cannot then raise the temperature up to the self-ignition oint.

The injection of the spirit through the pipe p is eected by means of a pump g, the plunger h of which is operated from the valve-gear shaft 'i by means of a'lever arran ement 7c for example, in which the size of t e eccentric Z must Ibe fixed according to at the pis-v t will be ad- I the predetermined law for the temperature inthe cylinder. It will be evident also that the movement of the lever c might be produced by its end being operated by a cam turning on a shaft. By the stroke of the plunger h in one direction the spirit is discharged into the working cylinder, while in the return stroke more s irit is sucked up from the storage tank nl t ough the pipe o. The pump must always be filled with spirit, without any air bubbles, in order that the law and the quantity of the spirit to lbe injected may not be disturbed owing to the compressibility of sfaid air bubbles. For this purpose a small air outlet cock m is placed on the ump', which cock will be opened during t e filling of the pump, but Will be closed during the feeding of the liquid by said ump.

By p acing the pressure valve of the spirit feeding system in the head of the cylinder, the pump can be guarded from the high pressure produced by the explosion. One method of producing this arrangement is as follows. The passage u leading into the cylinder, and by which the spirit will be injected, has a conical enlargement in .which a conical valve head g Fig. 2 fits in rider .toclose the passa e u, the valve being pressed uponits seat y a spring 1*. The springf-must be strong enough to resist the pressure upon the tube area during the explosionK A small piston t is mounted upon the narrow stem s of the valve and Works fluid tightly in the same, chamber as the valve head. The excess of the pressure surface of the iston t over that of the valve head is so a justed that the liquid forced by the pump is enabled by its pressure acting on t e said piston to overcome the force of the spring and to lift the valve from its seat. The space between the piston t and the opening leading to the cylinder must always be filled with spirit. An air outlet cock v must also be provided for use in the first filling as was the case in the ressure pump g. If the passage fet-leading into the cylinder is closed sufficiently tightlyby its valve head, the space remains filled with spirit whichcan not burn because no oxygen can obtain access to it in lar e motors several o enings of this kind wo d have to be provi ed leading into the cylinder. cyhnder w, and especially the cylinder head at the place where the spirit inlet. valve is arranged, must be well cooled in order that the spirit may always be well below its boilingpoint. For motors working with liquid fuel which will not mix with water two such pumps and injection valves must be provided, one for the liquid fuel and the other for the water.-

When the liquid fuel or 4iniiammable mat- Vter is very comBletely utilized it isr easily y in large motors, .to pro' possible, especia The j vide for a prolonged expansion by arranging in a suitable manner for the air inlet valve to be operated from'the valve-gear shaft in such a Wa that said valve is rst closed after the piston has made a part of its compression stroke. The remaining part -of the stroke then only serves for producing the compression, While for the expansion the who e stroke i's employed up to the opening of the exhaust slots. .Apart from this regulation of the inlet valve no alteration'need be made in the arrangement.

If it is desired to employ liquid `fuels which. are difficult to vaporize, such for instance as petroleum residues or crude oils, it will be Well in order to make sure of the va orization to Warm to a certain extent the lower partial pressure would be necessary to;

produce the condensation temperature after the mixture of the vaporized fuel with the air. For the ignition any suitable known method of ignition may be employed.

Having now particularly described and ascertained the nature of my said invention and inl what manner the same is to be per' formed, I declare that what I claim'is:

1. The method of cooling the explosive charge of an internal combustion engine to latter has been raised by the increase the capabilities of compression thereof, which consists in injecting a cooling liquid directly into the Working cylinder of an engine at a point during the compression of the charge When the temperature of the latter has been raised by the heat incident to said compression to a temperature equal to the boiling'point of the .cooling liquid and continuing the injection of said cooling liquid during the Jfurther compression of the charge.

2. The method of cooling the explosive charge of an internal combustion engine to increase the capabilities of compression thereof, which consists in injecting a cooling liquid directly into the working cylinder of an engine at a point during the compression of the charge When the temperature of the eat incident to said compression to a temperature equal to the boiling oint of the cooling liquid, and

then gradua y injecting such cooling liquid,

during the further compression of the charge so that. the heat produced by the compression during a part of the increase in pressure shall suffice to evaporate the cooling liquid injected during the same time, said evaporation serving to reduce the temperature of the charge. Y

l In testimony whereof I have signed myA name to this specification in presence of two. witnesses.

KARL EDMUND sriREBER.

' Witnesses JOHANNES HEYN, JULi-Us U'rcorrr. 

